Oldham drive engine

ABSTRACT

There is disclosed an Oldham&#39;s driving engine for taking out the maximum combustion pressure effectively from a top dead center in a piston engine as output for revolving an output shaft 17. A sliding block 11 is interposed between both flanges 8 and 9 to constitute an Oldham&#39;s coupling mechanism. One flange 8 is constituted as an idler flange 8, the other flange is constituted as an output flange 9, and an output end of a piston rod 4 is connected to the center of the sliding block 11. Further, a center line B 2  of both the flanges 8 and 9 is placed at a phase angle θ with the axial center B 1  of the cylinder in the reversed rotational direction of the sliding block 11. Furthermore, a plurality of engines described above are placed side by side and connected to each other, and the idler flange 8 rotated in linkage with the sliding block 11 is axially supported to the inside of each engine case 7 between the mutually adjacent engine cases 7, so that a multiple cylinder engine can also be constituted for providing the output from each piston together to the output shaft of the engine case 7 of the engine arranged at the final end.

TECHNICAL FIELD

This invention relates to an engine for transmitting pressure receivedby a piston within a cylinder to an output shaft as effectively aspossible in a piston engine, and more particularly to an Oldham'sdriving engine for allowing large expansion energy at the moment whenthe piston is moved from a top dead center toward a bottom dead centerto output effectively as the torque for revolving the output shaft.

PRIOR ART

As for an engine which has been practically in wide use in a prior art,a piston engine for transmitting the reciprocating motion of a cylinderto a crankshaft as a rotational motion through a rod and a crank, and arotary engine having a combustion chamber provided around a rotor torotate directly the rotor have been known. However, the rotary engine isonly used for one having special specifications by reason of high fuelcost or the like, although an output shaft is revolved smoothly toresult in sufficient output efficiency.

On the other hand, in the prior art piston engine, it has been knownfrom the combustion-dynamical point of view that the pressure in thecylinder becomes maximum at the time of an explosion under the conditionthat the piston is located at the top dead center position, and that thepressure is rapidly reduced immediately after the starting of a pistonoperation after the explosion.

However, when the piston is located at the top dead center position, apiston rod and a crank arm are in a rectilinearly connected state on theaxial center of the cylinder. In this state, it is mechanicallyimpossible to convert the extrusion energy of the piston rod into therotation energy of the crank arm. In order to compensate for suchdisadvantages, a flywheel is mounted on the side of a crankshaft.However, such a problem as the energy transmission efficiency of themaximum combustion pressure immediately after the explosion is extremelybad remains unsolved.

It is an object of the present invention to provide an Oldham's drivingengine for taking out the maximum combustion pressure in theneighborhood of a top dead center of a piston to an output shafteffectively so as to dissolve the problems described above.

DISCLOSURE OF THE INVENTION

The present invention relates to an engine constituted such that acylinder for allowing a piston connected to the tip end of a rod toinsert thereinto is fixed to a case for rotatably and axially supportingan output shaft revolved in linkage with the reciprocating motion of thebasal end of the rod.

A flange,shaped sliding block is accommodated in the case, and connectedto the end of the rod as being rotatably and axially supported thereto.An idler flange rotatably and axially supported to the inside surface ofthe case and an output flange fixed to the output shaft are provided onboth sides of the sliding block through a certain distance between theaxes of both the idler flange and the output flange. Also, irregularstripes slidably fitted to each other and alternately crossing areformed on both surfaces of the sliding block and the inside surfaces ofboth the idler flange and the output flange.

According to the engine of the present invention constituted asdescribed above, high driving force of the piston is obtained at theslight moment when the combustion pressure becomes maximum at the timeof combustion at the top dead center position of the piston in thepiston engine, and then the obtained high driving force can betransmitted to the output side at the efficiency extremely higher thanthat in case of using a prior art crankshaft. As a result, the amount ofenergy to be taken out to the output side becomes also large, and theoutput shaft can be smoothly revolved as well.

Further, since the revolving speed of the output shaft with respect tothe piston driving force is reduced to half in comparison with that of acrankshaft type, a speed reducing mechanism can be omitted by thecorresponding part.

Furthermore, according to the engine of the present invention, the axialcenter of the idler flange and that of the output flange are arranged tobe symmetrical in rotation to the axial center of the cylinder, and astraight line interconnecting the axial centers of both the flanges isplaced at a certain phase angle with the axial center of the cylinder inthe reversed rotational direction of the sliding block. As a result, theforce for revolving the output shaft can be transmitted to the outputshaft most efficiently from the moment when the piston is started fromthe top dead center. Therefore, the explosion engine in the cylinder canbe outputted effectively.

Furthermore, the engine according to the present invention can be alsoconstituted such that a plurality of combinations of the cylinder andthe case are placed side by side, then connected and fixed to eachother, the idler flange connected to the side surface of the slidingblock within each case through the irregular stripes is rotatably andaxially supported to a partition portion of the mutually adjacent cases,and the output shaft is provided in the case arranged at the end of aplurality of connected cases.

According to the mechanism described above, the outputs from a pluralityof engines are gathered to one output shaft to constitute a multiplecylinder engine, so that a high-powered output can be obtained.

Further, even in the multiple cylinder engine described above, the axialcenters of two idler flanges in each case or the axial centers of boththe idler flange and the output flange are arranged to be symmetrical inrotation to the axial center of each cylinder, and a straight lineinterconnecting the axial centers of both the flanges is placed at acertain phase angle with the axial center of the cylinder in thereversed rotational direction of the sliding block, so that an efficientoutput can be obtained from the moment when the piston is started fromthe top dead center.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view showing an engine as an embodiment of thepresent invention;

FIG. 2 is a sectional view taken along a line II--II in FIG. 1;

FIG. 3 is a view, partly omitted, for explaining an engine correspondingto that shown in FIG. 1 and a method for measuring the output of theengine;

FIG. 4 is a view for explaining a prior art piston engine and a methodfor measuring the output of the engine;

FIG. 5 is a graph showing the comparison of the output of an Oldham'sdriving engine shown in FIGS. 3 and 4 with that of a prior art pistonengine;

FIG. 6 is a graph showing the comparison of the output of an Oldham'sdriving engine with that of a prior art piston engine on the basis of anexperiment conducted under the conditions different from those in FIG.5; and

FIG. 7 is a sectional view showing an embodiment in case of constitutinga two cylinder engine based on an Oldham's driving engine.

BEST MODE FOR EXECUTING THE INVENTION

FIGS. 1 to 3 are views respectively showing the principle structure ofan engine as an embodiment of the present invention. In this engine, apiston 2 is inserted into a cylinder 1, a combustion chamber 3 is formedon the side of a cylinder head provided with suction and exhaust ports5a and 5b, one end of a piston rod 4 is connected to the rear (bottom)side of the piston 2 through a connection shaft 6, and an output end ofthe rod 4 is inserted into an Oldham's case 7 which will be described inthe following.

The Oldham's case 7 has an idler flange, 8, an output flange 9 and asliding block 11 (which will be described later) built-in. The Oldham'scase 7 takes the circular shape when observed from the front so as tohave a space enough to rotate (revolve) the sliding block 11 along acircular orbit 12. An upper end of the Oldham's case 7 has a cylindricalopening 13 which is connected to a lower end opening of the cylinder 1at a flange portion 14 provided on an outer peripheral edge of theopening 13.

The idler flange 8 having a disc shape is fitted and supported to theinterior rear side of the Oldham's case 7 rotatably by a bearing portion16. The output flange 9 is supported to the interior front side of theOldham's case 7 rotatably and axially by an output shaft 17 such thatthe output flange 9 is in parallel to the idler flange 8 and located atthe position lower than the idler flange 8 through a certain distance Lbetween the axes of both the flanges. Both the output flange 9 and theoutput shaft 17 are axially supported to a housing 18 used in common fora cap detachably fitted to the front side of the Oldham's case 7. Boththe flanges 8 and 9 or the like are axially supported by properlyinserting wear-resistant ceramic bearings or any other bearings. Whenthe peripheral surface of each flange works as a sliding surface, an oilline (oil channel) is formed on the peripheral surface.

The sliding block 11 having a spool shape and composed of two circularplates 10a and 10b integrally connected to each other at the center ofboth the plates by a shaft 19 is inserted between the idler flange 8 andthe output flange 9, and a boss 20 provided at the output end of the rod4 is connected to the shaft 19. Further, the opposed surfaces of boththe flanges 8 and 9 and both surfaces of the sliding block 11 arerespectively provided with irregular stripes 8a and 11a and irregularstripes 11b and 9b, which respectively pass through the center points ofboth the flanges and the sliding block and are fitted to each other soas to be slidable in the normal directions thereof. The irregularstripes 8a and 11a and the irregular stripes 11b and 9b take such thecross shape as being orthogonal to each other when observed from thefront. The section of each irregular stripe may be either arcuate orrectangular or the like as illustrated in the drawing.

The combination of the idler flange 8, the output flange 9 and thesliding block 11 originally constitutes an Oldham's coupling mechanismthat if either of the flanges 8 and 9 rotates, the rotation of either ofthe flanges 8 and 9 can be transmitted to the other flange throughrotation and revolution of the sliding block 11. Then, in thisembodiment, when the piston 2 is operated to retreat (descend) due tothe generation of combustion pressure under the condition that thepiston 2 is located at a top dead center A₁ as shown in FIGS. 1 and 2,the sliding block 11 rotates (revolution) clockwise along the circularorbit 12 of the sliding block while rotating (rotation) in the samedirection due to the tilting and sliding action of the irregular stripes8a and 11a and the irregular stripes 11b and 9b. At the same time, boththe output flange 9 and the output shaft 17 are driven clockwise. Atthis time, the idler flange 8 rotates freely, and the output shaft 17revolves in a half of round by rotating and revolving the sliding block11 once, so that the revolving speed of the output shaft is reduced tohalf. In a two cycle engine, for instance, an explosion process iscontained twice during one revolution of the output shaft 17.

Further, in the embodiment, the axial centers of both the idler flange 8and the output flange 9 are arranged to be symmetrical in rotation tothe axial center B₁ of the cylinder 1, and the center line B₂interconnecting the axes of both the flanges 8 and 9 placed at a certainphase angle θ (e.g., 35°) with the axial center B₁ in the reversedrotational direction of the sliding block 11. Then, the force forrevolving the output shaft 17 can be transmitted to the output shaft 17most efficiently at the moment when the piston 2 is started from the topdead center A₁.

In FIG. 3, when the axial centers of both the flanges 8 and 9 arerespectively defined as O₁ and O₂ and the moving points on therevolution orbit 12 of the shaft 19 are respectively defined as P₁, P₂.. . , the rotational arms with respect to the output shaft 17 arerespectively expressed by P₁ to O₂ when the piston 2 is located at thetop dead center A₁. Similarly, when the arbitrary position of the piston2 immediately after the combustion is defined as A₂, the rotational armsto the output shaft are respectively expressed by P₃ to O₂ in the movingpoint P₂ of the shaft 19 when the piston 2 is located at the positionA₂. These arm lengths are sequentially varied depending on the rotationand revolution of the sliding block 11. Then, it is apparent that therotational arm to the output shaft becomes longest when the piston 2 islocated at the top dead center A₁, and the torque for revolving theoutput shaft 17 is made smallest at that time as well. Reference symbolA₄ designates a bottom dead center position of the piston 2. The shaft19 is moved to the position, which is on the axial center B₁ of thecylinder 1 and at the lowest position of the revolution orbit 12, whenthe piston 2 is located at the bottom dead center position A₄.

In this connection, when the centers O₁ and 0₂ of both the flanges 8 and9 are located on the axial center B₁ of the cylinder (i.e., when anyphase angle θ is not provided), no action for rotating the arms P₁ to O₂can be expected at the initial operation time of the piston 2, and it isnot preferable as an initial operating position.

FIG. 5 is a graph showing the difference of revolving force of theoutput shaft 17 by using a mechanism of an engine (FIG. 3) of theembodiment indicated by a symbol a and a mechanism of a prior art pistonengine (FIG. 4) indicated by a symbol b on the basis of the measurementand comparison according to a model experiment. Namely, in theexperiment of the embodiment, a measurement arm 21 is attached to theoutput shaft 17 as shown in FIG. 3 to apply a certain load to the piston2 from above, and the torque T at the tip end of the measurement arm 21is measured in correspondence to the change of a rotational angle β ofthe arm 21.

FIG. 4 shows a prior art piston engine mechanism. In FIG. 4, thecylinder 1, the piston 2 and the rod 4 or the like are respectivelydesignated by the same reference numerals as the corresponding parts ofthe engine mechanism in the embodiment described above, and thedimension of each part is made identical to that of the Oldham's drivingengine shown in FIGS. 1 to 3.

The measurement conditions in each mechanism described above are asfollows:

cylinder bore : 40 mm

piston stroke : 40 mm

length of piston rod : 100 mm

length of measurement arm : 150 mm

pressure (load) applied to piston: 4 Kg (constant)

(Note) The rotational angle of the measurement arm 21 is taken as avariable in any case of the measurement. However, since the revolutionratio of the output shaft 17 is 1/2 in the embodiment, the same outputchange is repeated twice during the actual revolution of the outputshaft 17. Further, as has been described above, the combustion pressurewithin the cylinder 1 is rapidly reduced with the piston operation afterthe combustion, and the output shaft 17 hardly acts on the piston asoperating force at the point of time when the rotational angle exceeds90° after the starting, so that the measurement at the position wherethe rotational angle of exceeds 100° after the starting of the outputshaft 17 will be omitted.

According to the result of measurement, the output efficiency of thepiston 2 to the output shaft 17 in the embodiment expressed by thesymbol a is extremely high from the moment of the starting, incomparison with the output efficiency of that in the prior art cranktype piston engine expressed by the symbol b. When such extremely highoutput efficiency is continued up to the neighborhood of approximately90° after the starting of the output shaft, the output efficiencyindicated by the symbol a is approximately more or less 1.6 times aslarge as the output efficiency indicated by the symbol b according tothe cumulative output ratio.

In this connection, the measurement described above is made as theresult of applying a constant load of 4 Kg to the piston 2. However, incase of the piston engine accompanying the combustion actually, sincethe combustion pressure shows an abrupt rising from the moment ofignition as described above, all the resultant maximum pressure iseffectively converted to the piston driving. Therefore, the differencein the torque yielded in the output shaft 17 immediately after thestarting from the actual top dead center of the piston becomes stilllarger than that shown in FIG. 5.

FIG. 6 is a graph on the basis of the measurement and comparisonaccording to a model experiment conducted under the following conditionsdifferent from those shown in FIG. 5 (the different conditions are shownby asterisk mark as described below) as the conditions of a mechanism ofan engine of the present invention and a mechanism of a prior art pistonengine.

cylinder bore : 40 mm

piston stroke : 41 mm

length of piston rod : 100 mm

length of measurement arm : 210 mm

pressure (load) applied to piston: 7 Kg (constant)

When comparing FIG. 5 with FIG. 6, the torque at the time of startingthe piston driving from the top dead center of the piston of theOldham's driving engine (when the rotational angle of the output shaftis 0) is 800 g in case of FIG. 5, while the torque described above is 0in case of FIG. 6. There is a difference in starting output between thecases in FIGS. 5 and 6. It is to be understood that the differencedescribed above is caused by a slight error in the angle of theirregular stripes of the sliding block or the like at the time ofmeasurement. However, the cases in FIGS. 5 and 6 are quite the same insuch points that a highly rising output is provided in comparison withthat in case of the prior art piston engine, and the action according tothe present invention is excellent.

Incidentally, only the basic structure of the engine is shown in theillustrated embodiment. However, it is a matter of course that a balanceweight and a flywheel are desirably mounted on the side of the shaft 19and the output shaft 17 in order to actually obtain the stable revolvingforce from the output shaft 17. Further, in the engine of the presentinvention, the revolving speed of the output shaft 17 to the pistondriving is reduced to half in comparison with that in the prior artengine of a crankshaft type. However, the normal engine output islargely reduced at a driving portion for operation. Therefore, there isan advantage in that a speed reducing mechanism can be omitted by thecorresponding part, and the engine of the present invention does notoffer any practical problem.

FIG. 6 shows an embodiment in case of constituting a two cylinder enginebased on the engine of the present invention. In this embodiment, thecylinder 1 and the Oldham's case 7 are continuously provided as shown inthe drawing, a spool-shaped flange composed of two flanges 8 and 8coaxially fixed to each other by a shaft 21 is rotatably and axiallysupported to a partition 7a within the Oldham's case 7, and both thesliding blocks 11 are connected to the flange. A housing 18 is mountedon the Oldham's case 7 on the left side in the drawing to axiallysupport an idler flange 8, and the revolving force of the sliding block11 on the left side is transmitted to the output shaft 17 through theflange 8, the sliding block 11 on the right side and the flange 9. Thepiston 2 on the left side is provided at such a position as smoothrevolving force can be yielded in the most efficient phase to the piston2 on the right side. Further, it is also possible to increase the numberof cylinders to constitute a multiple cylinder engine.

INDUSTRIAL POSSIBILITY OF UTILIZATION

As described above, the Oldham's driving engine of the present inventioncan be utilized as a prime mover in a wide field similarly to the caseof a prior art crank type piston engine and a rotary engine. Forinstance, the engine of the present invention can be utilized as anengine for automobiles, various kinds of working machines, workingvehicles and generators or the like.

I claim:
 1. An Oldham's driving engine comprising a cylinder having anaxial center line, a piston slidably positioned in said cylinder, a rodhaving a tip end connected to said piston and a basal end, an outputshaft, a case rotatably and axially supporting said output shaft forrotation in linkage with reciprocating motion of said basal end of saidrod, a sliding block accommodated in said case and connected to androtatably and axially supported on said basal end of said rod, an idlerflange rotatably and axially supported on an inside surface of the casean output flange fixed to the output shaft and rotatably and axiallysupported on another inside surface of the case, said idler flange andsaid output flange being provided on both sides of said sliding blockthrough a certain distance between rotational axes of both flanges, andirregular stripes slidably fitted to each other and alternately crossingprovided on both surfaces of said sliding block and on inside surfacesof both said idler flange and said output flange, wherein an axialcenter of said idler flange and an axial center of said output flangeare arranged to be symmetrical in rotation to said axial center line ofsaid cylinder; and a straight line interconnecting said axial centers ofboth said flanges is placed at a predetermined phase angle with saidaxial center line of said cylinder in the reversed rotational directionof said sliding block.
 2. An Oldham's driving engine according to claim1, wherein a plurality of combinations of said cylinder and said caseare placed side by side, then connected and fixed to each other, saididler flange within each case is rotatably and axially supported on apartition portion of the mutually adjacent cases, said output shaft isprovided in the case arranged at one end of said plurality ofcombinations of connected cases, and said axial centers of two idlerflanges in each case or said axial centers of both said idler flange andsaid output flange are arranged to be symmetrical in rotation to saidaxial center line of each said cylinder of each of the combinations.